The present invention relates to an amplification device for a satellite suitable for flexibly distributing a plurality of received transmission channels to an output beam signal.
In the usual space mission situation, the change in satellite transmissions to users equipped with transmit/receive terminals of reduced capacity and of small dimension requires an increase in the quality of reception of the onboard segment and an increase in the power of the signals retransmitted to the ground. These performance increases are obtained by increasing the onboard antenna gains, which can be achieved only by reducing the dimensions of their ground coverages. These coverage reductions require, in order to cover a particular geographic coverage zone on the ground, generating several beams or spots in order to sample the geographic zone. Such multibeam or multispot coverages make links with small ground terminals possible but they pose the problem of managing the onboard capacities and more particularly the allocation of the received channels to the transmitted beams according to:                the different traffic densities,        changes in traffic densities over time.        
Therefore, in a known manner and as shown schematically in the architecture 1 of FIG. 1, a satellite receives two signals each corresponding to a transmission channel and supplies a beam at the output. The two channels are processed by one input section 2 which carries out:                a low-noise reception, an adequate frequency conversion and a filtering suitable for each of the two transmission channels,        a delivery of each of the two channels to an amplifier 3.        
A transmission channel corresponds to a transmission frequency band and may correspond to a single carrier or a set of carriers or subchannels.
Each transmission channel is amplified by the amplifier 3 that is associated with it. The amplifiers 3 are high-power amplifiers and are usually produced by linearized traveling wave tubes or solid state amplifiers. In order to have several channels per beam, it is necessary to combine the channels through output multiplexers 4. The output multiplexer 4 (or OMUX) provided at the output of each amplifier, known to those skilled in the art, comprises filters and a common guide which is designed to combine the transmission channels after they have been amplified. In the situation of FIG. 1, the output multiplexer 4 receives two transmission channels and supplies one beam signal. The beam signal is then sent to a source not shown such as a horn which radiates to a reflector not shown for the formation of the beam. Therefore, such an architecture makes it possible to have two transmission channels per beam on the downlink.
However, this architecture is not flexible and combines channeled amplification (one amplifier per channel and recombination of the channels through the OMUX) with a passive antenna. This solution imposes a fixed frequency plan (which defines the OMUX solution) without the possibility of modification in orbit.
The operators do not always have very clear visibility of the future distribution of the traffic (and therefore of the power) on the coverages addressed and therefore need to have a certain flexibility making it possible to adapt during the lifetime of the satellite to the traffic needs resulting from demand and from the success of services in various geographic zones. It is therefore important to be able to route the transmission channels in a flexible manner to the beams, that is to say so that the total number of channels processed by the useful load can be distributed to the various beams in accordance with the traffic demand throughout the lifetime of the satellite. With respect to this, the architecture as shown in FIG. 1 does not allow any flexibility in terms of number of channels allocated per beam and requires a number of amplifiers that is imposed by the number of channels to be amplified. It is not possible, in the prior art as explained, to be able to generate any one channel in a possible set of channels or else to be able to vary the frequency plans during the lifetime of the satellite.